Optical preamplifier with one amplification unit

Abstract

An optical preamplifier with an amplification unit is for amplifying an optical signal and compensating dispersion of the optical signal after receiving the optical signal from an optical transmitter, and thereof for supplying the optical signal to an optical receiver. The optical preamplifier includes a first wavelength division multiplexor WDM 1 for multiplexing the inputted optical signal and a pumping light, an erbium doped fiber EDF for amplifying the optical signal multiplexed in the WDM 1 in maximum, while non-linear phenomena do not happen in a following dispersion compensating fiber module DCFM, an optical isolator band pass filter ISOF for passing only the optical signal with a bandwidth of a predetermined wavelength among the optical signal amplified by EDF, the DCFM for damping an optical intensity of the optical signal within the optimum level of the optical signal for the optical receiver, while compensating the dispersion of the optical signal from the ISOF, and a first tap coupler dividing the optical signal from the DCFM in constant ratio for controlling the optical intensity of the pumping light and for being outputted to the optical receiver.

What is claimed is:  
     
       1. An optical preamplifier with one amplification unit for amplifying an optical signal, compensating dispersion of the optical signal after receiving the optical signal from an optical transmitter and supplying the optical signal to an optical receiver, the optical preamplifier comprising: 
       a first wavelength division multiplexer for multiplexing the optical signal and a pumping light;  
       an erbium doped fiber amplifying the optical signal multiplexed in said first wavelength division multiplexer;  
       an optical isolator band pass filter for passing only the optical signal with a bandwidth of a predetermined wavelength among the optical signal amplified by said erbium doped fiber;  
       a dispersion compensation fiber module for damping an optical intensity of the optical signal within an optimum level of the optical signal for the optical receiver, while compensating the dispersion of the optical signal from said optical isolator band pass filter, the optical signal in said erbium doped fiber is amplified in a range of preventing a non-linear phenomena in said dispersion compensation fiber module; and  
       a first tap coupler for dividing the optical signal output from said dispersion compensation fiber module in a constant ratio, and for outputting the optical signal to a circuit to control the optical intensity of the pumping light and to the optical receiver.  
     
     
       2. The optical preamplifier of  claim 1 , further comprising: 
       a second tap coupler, installed before said dispersion compensation fiber module, for dividing a portion of the optical signal;  
       a photo detector for detecting an optical intensity of the optical signal by using the optical signal divided in said second tap coupler; and  
       an optical isolator, installed between said second tap coupler and said first wavelength division multiplexer, for interrupting a retrogression of the optical signal.  
     
     
       3. The optical preamplifier of  claim 1 , further comprising a second wavelength division multiplexer for multiplexing an inputted optical signal and second optical signal into an optical signal of the bandwidth of a predetermined wavelength. 
     
     
       4. The optical preamplifier of  claim 3 , further comprising a second tap coupler dividing the optical signal of the bandwidth of the predetermined wavelength from said second wavelength division multiplexer into a signal for monitoring loss in the optical signal and a second optical signal. 
     
     
       5. The optical preamplifier of  claim 4 , further comprising an optical isolator for amplifying the second optical signal from said second tap coupler and passing onto said dispersion compensation fiber module. 
     
     
       6. The optical preamplifier of  claim 1 , further comprising a second tap coupler, installed before said dispersion compensation fiber module, for dividing a portion of the optical signal. 
     
     
       7. The optical preamplifier of  claim 6 , further comprising a photo detector for detecting an optical intensity of the optical signal by using the optical signal divided in said second tap coupler. 
     
     
       8. The optical preamplifier of  claim 6 , further comprising an optical isolator, installed between said second tap coupler and said first wavelength division multiplexer, for interrupting a retrogression of the optical signal. 
     
     
       9. The optical preamplifier of  claim 1 , further comprising an optical isolator, installed before said dispersion compensation fiber module, for interrupting a retrogression of the optical signal.